Radars and other instrumentation and devices used in the normal target tracking environment are frequently mated with optical viewing and monitoring systems. The optical viewing and monitoring systems are used to obtain direct and real-time observations of the spatial areas being illuminated or sensed by the radars or sensors respectively. In such applications the optical systems which may include those employing vidicons or similar devices that are susceptible to being damaged by impingement of sunlight or other intense and destructive radiation require protective measures. In a specific application, for example, where a vidicon camera is mated to a radar or tracking camera, it is necessary to maintain the vidicon observation and recording of the spatial area being covered by the radar without damage to the vidicon tube. If the vidicon camera is not protected, the phosphors in the vidicon tube can be permanently burned and destroyed. If the vidicon camera is thus permanently disabled the camera is a financial loss and, since the test involving the use of this equipment must be scrubbed and rescheduled without prior warning, substitute tests cannot be inserted in the schedule hole caused by the scrubbed test and a very expensive test opportunity time slot is lost. Total cost of financial loss alone may be substantial.